Japan Post has issued a stamp set commemorating the 50th anniversary of the Antarctic Treaty.
The Antarctic Treaty regulates international relations with respect to Antarctica, Earth's only continent without a native human population.
The treaty, entering into force in 1961 and eventually signed by 47 countries, sets aside Antarctica as a scientific preserve, establishes freedom of scientific investigation and bans military activity on that continent.
The stamps depict:
Snow pattern and the silhouette of Antarctica
The Adelie penguin
The Chinstrap penguin
The Emperor Penguin
The Macaroni penguin